The disclosure pertains generally to powered clamps and more particularly to a powered clamp having a fail safe lock.
It is well known to employ powered clamps to retain sheet metal panels during welding or other assembly plant operations. Examples of such powered clamps include U.S. Pat. No. 5,165,670 entitled “Retracting Power Clamp” issued to Sawdon on Nov. 24, 1992, and U.S. Pat. No. 5,118,088 entitled “Power Clamp” which issued to Sawdon on Jun. 2, 1992; both of which are incorporated by reference herein. Traditional power clamps, however, are prone to unclamping the panel if the fluid pressure is lost. This can lead to damaged or misaligned parts.
More recently, detent and plunger arrangements, and offset piston mechanisms have been provided in an effort to overcome the traditional pressure lost concerns. For example, reference should be made to U.S. Pat. No. 6,378,855 entitled “Locking Pin Clamp” which issued to Sawdon et al. on Apr. 30, 2002, and U.S. Pat. No. 6,059,277 entitled “Retracting Power Clamp” which issued to Sawdon et al. on May 9, 2000; both of which are incorporated by reference herein. Notwithstanding, while the above-identified patents disclose significant inventions, there is still room for further improvement.